Fall Armyworms Are Ravaging Crops in Many African Countries

"They've finished eating the wild plants and are now going into the villages where there is more vegetation. They eat everything in their path. All plant life is at risk."

by Julie WalkerJun 29, 20175 minutes

Fall armyworm from the Canadian Biodiversity Information Facility – Public Domain

As African economies begin to emerge from the global financial crisis of the last decade, a new threat to the agricultural sector in many countries may slow recovery: the invasion of the fall armyworm (Spodoptera frugiperda).

Originally from the Americas, the fall armyworm was first detected in west and central Africa at the beginning of 2016 (Sao Tome and Principe, Nigeria, Benin, and Togo). About a year later, it was found in Angola, Botswana, Kenya, Malawi, Mozambique, Namibia, Niger, Rwanda, Sierra Leone, South Africa, Tanzania, Uganda, Zambia, and Zimbabwe. And the invasion isn't showing signs of stopping anytime soon.

The larva of the fall armyworm, originally from the Americas, was recently introduced into Africa and has already wreaked havoc on grain crops. Corn has been especially affected in Zambia, Zimbabwe, South Africa, and Ghana. According to the UN, Malawi, Mozambique, and Namibia have been similarly afflicted.

These caterpillars eat southern African food staples, such as corn, wheat, millet, and rice. Southern Africa has already been hit by one of the worst droughts in recent years.

The caterpillar invasion has caused terrible damage in the affected countries. As a result, the Food and Agriculture Organization (FAO) convened an emergency meeting in Zimbabwe during which experts from 13 countries gathered to adopt a strategy for fighting this disaster. A local journalist, Sally Nyakanyanga, reported on the story for humanitarian crisis news site IRIN:

Spodoptera frugiperda is a formidable foe. Pesticides only work when the larvae are very small and before they have begun to cause visible damage to the crop. After that, there are no quick fixes. The pest can cause crop losses of more than 70 percent.

Sally Nyakanyanga went on to describe a farmer who tried to get rid of the caterpillar with the crop protection products that he had used in the past against native armyworms. But, because the fall armyworm is a different species, these products had no effect:

Vavariro Mashamba, 51, hoped to harvest 10 tonnes of maize from each of the 20 hectares he planted in his farm in the Karoi district, in north-central Zimbabwe. But when he started to see ragged holes on the foliage of his crop and sawdust-like frass near the whorl and upper leaves of the plants, he knew he was in trouble. His best hope now is a yield of six or seven tonnes per hectare.

“At first I thought it was the African armyworm (Spodoptera exempta) that was damaging my crops. I bought Carbaryl pesticide and sprayed on the plants. There was no change. Instead, the worms continued to multiply in my field,” Mashamba told IRIN.

Experts from the Ministry of Agriculture visited his farm, but by then it was too late to eradicate the fall armyworm (The “fall” part of the name comes from the caterpillar’s feeding habits: In its native Americas, it does most damage in late summer and early autumn – or “fall” in US English. See here for more details).

As recently as early June 2017, Guinea was not on the FAO's list of affected countries, but fall armyworms have now been found there, too. Journalist Ousmane Koumanthio Tounkara spoke to Abdoulaye Kaloga Diallo, an official in charge of protecting vegetation, for an article on local news site Aminata:

Some particularly voracious armyworms have been ravaging the Mali prefecture since the end of May and have invaded 21 villages in rural Yembering, attacking the wild plant life.

As of mid-year, 250 hectares of vegetation have been eaten by the unwelcome visitors. Those charged with protecting the vegetation think that the lack of rain has something to do with the catastrophic invasion of so many insects.

As effective resources remain unavailable, no response has been made beyond public awareness campaigns.

Abdourahamane Barry, from the collaborative website Guinéenews, thinks that the situation is even more serious. He reported that the infestation has already killed some regional farmers’ livestock:

After invading the Mali, Tougue, Labe, and Koubia prefectures, these unwelcome caterpillars have now reached Dondé, a district within the Parawol sub-prefecture in the Lélouma prefecture. The destructive caterpillars are eating nearly everything in their path.

Guinéenews’ local editor spoke to the regional head of vegetation protection, who confirmed the presence of the caterpillars.

“There are, undoubtedly, caterpillars in Labe's five prefectures. These insects are damaging the crops. They've finished eating the wild plants and are now going into the villages where there is more vegetation. They eat everything in their path. All plant life is at risk,” explained Alpha Oumar Bah.

In some areas, goats as well as vegetation, have fallen victim to these caterpillars. Eleven goats in Diogoma, in the Sannoun sub-prefecture in the Labé prefecture, are dead after having grazed on leaves on which the caterpillars were perched.

Clearly, this larva is already an extreme nuisance that eats everything it possibly can. As a moth, it can travel more than 100 kilometers and reproduce quickly. In an area of the world already known for its food insecurity, the devastating consequences of this invasion are difficult to predict.